Arc-lamp.



J. T. H. lDEMPSTBRl ARG LAMP. APPLICATION IIILBD MAY 1. 1905.

Patented oet, 5, 1909.

John 7T MTM/:35E

UNITED STAT/Es PATENT OFFICE.

JOHN T. H. DEMPSTB, OF SCHENECTADY, NEW YORK, ASSIGEQR. T0 GENERAL ELEC- TRIO COMPANY, A COBPORAATIQON 0F NEW YORK.

Anc-LAMP.

Specification of Letters Patent.

Patented Oct. 5, 1909.

Application led Hay; 1, 190B. Serial No. 258,209.

To all whom fit may concern:

Be it. known that I, JOHN T. H. DnMrsTER, a citizen of the United States, residing at Schenectady, county of Schenectady, State, of N ew York, have invented certain new and useful, Improvements in Arc- Lamps, of which the following isa specification. V

My present invention relates to are lamps and more particularly to arc lamps in which the electrodes employed are so slowly consumed by the action of the arc thatit is unnecessary to provide means for automatically feeding the 'electrodes in order to compensate for the electrode consumption.

My invention comprises certain features of construction and arrangement in are lamps of more or less general utility but peculiarly'adapted for use in arc lamps with non-feeding electrodes.

The varlous features of novelty which characterize my invention are p'ointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of my invention, however, reference may be had to the accompanying drawings and descri tion in which 1 have illustrated and descri ed one form in which my invention may be embodied.

Of the drawings, Figure 1 is a vertical axial section of an are lamp showing some parts in elevation; Fig. 2 is a partial section on the line 2 2 of Fig. 1 looking up; Fig. 3 is a partial section on the line 3 3 of Fig. 1; Fig. 4 is a perspective view of one of the scrapers and of a portion of an auxiliary electrode but disconnected from the scraper, and Fig. 5 is a perspective view of a portion of the structure shown in Fig. 3.

Referring to the drawings, 1 represents the top member of the lamp proper provided with means such as a. porcelain pulley or roller 2 by which the lamp may be supported. The member 1, which is tubular, is internally threaded to receive the upper end of the externally threaded tubular member 3 which forms the back-boneof the frame work of the lamp. A nut 4 threaded on the upper end of the member 3 below the top member 1 clamps a hoodl 5 in place. The hood 5, which may loe-formed of sheet metal, is symmetrical-with respect to the member 3 and has a hole formed in it throughl which the member passes. The lower end of the member 3 supports a platform 6. In the construction shown the platform G is aper- 'tured to receive the lower end of the member 3 which is fia-red out to engage and support the platform 6. A tubular magnetizing coil or winding 7 surrounds the member 3 and rests on the latform 6. It will of course be understoo that the Winding 7 is suitably insulated from the member 3 and the platform 6.

The inner wall of a double walled casing extends from the platform 6 to the hood 5. As shown, the inner wall 8, which is cylindrical, fits tightly against the under surface of the hood 5 which may have a shoulder 9 formed as shown against which the upper end of the casing 8 abuts. The lower end of the casing 8 closely embraces the periphery of the platform 6 to which it is secured by screws 10. The outer`wall 11 of the casing which'is concentric with the inner wall is separated therefrom by two annular spacing members 12 placed onenear the upper end of the wall 11 and one near the lower end of the Wall 11. rlhe members 12 are formed with radially extending passages 13 which register with apertures formed for the purpose in the Walls 8 and 11. Through the apertures 13 in the lower member 12 air may enter the chamber 'between the platform 6, hood 5 and Wall 8 to cool the mechanism contained therein. The heated currents of air pass out of this chamber through the passages 13 formed in the upper member 12. The members 12 are formed with passages 15 Which extend parallel to the member These passages permit the passage of air currents through theV annular space between the walls 8 and l1 in a direction parallel to the axis of the casing walls.

Hoods or guards 16 are secured to the outer casing wall to prevent the entrance of dirt or moisture into the interior of the casing Wall 8v through the passages 13. -The members 12 may be secured to the inner casing by rivets 1 .7 and the outer casing wall may be secured to theinner casing wall vby screws 18 which pass through the two walls and through separating washers 19. As shown, the upper end of the casing wall 11- terminatcs some distance below the adjacent portion of the hood member 5 which serves as a ard to. prevent' dust or` moisture from entering the space between the walls 8 and 11.

Chambered member-20, shaped like an inverted bell and preferably formed of some material having good heat conductivity such as sheet brass or copper, is secured to the platform 6. In the construction shown the upper end of the member 20 is formed with a cylindrical portion 20 which embraces the lower end of the casing wall 3 and is secured to the platform 6 by the screws 10. The lower end of the bell-shaped member 20 which is closed has secured to it, as by screws 22, the upper and positive non-consuming electrode 23 of the lamp which in the construction shown and described comprises a cylindrical block of metal 24. The metal of the block 24 is preferably formed of some material which is a goed conductor both of heat and electricity, and is not readily oxidized. The lower end of the electrode 23 may advantageously be formed of silver. In the construction shownY a disk 25 formed of silver is secured to the lower end of the block 24. Diametrically opposed slots 2G are formed inthe member 20 at its lower end. Through these slots project. the horizontal arms or L-shaped members 27. Each member 27 comprises a horizontal arm and a downwardly extending arm. The inner ends of the members 27 are pivotally connected to a cross-head 27 located within the chambered member 2O which is connected to the lower end of a plunger or core 23 formed of magnetic material, the upper end of which extends into the tubular member 3 in which it has a sliding fit. To the upper end of the member 28 is connected one end of a coiled flexible conductor 29, the other end of which is secured to the member 3 by a clamping screw 30.

An extension 30 of theouter casing wall 11 supports the upper end ofthe hollow member 31, shaped like a truncated cone, both ends of which are open. The' member 31 surrounds the member 20 from which it 1s separated by a space annular in cross-section. To the lower en d of the member 31, which is about on a level with the lower end of electrode 23, are secured at diametrically opposed points, arms 32. The arms 32, which are similar to each other, are L-shaped each comprising an upper vertical portion and a lower horizontal portion. The lower horizontal portions are bent to form a socket in which is secured the lower electrode 33 of the lamp by screws 34 which members 32 together.

The electrode 33 is in line with the electrode 23 from which it isv separated by the arc length. As shown, gravity holds the lower ends` of the downwardly extending arms of the members 27 in engagement with the periphery of theelectrode 33 with some force when the parts are inthe position shown 1n the drawings. When the winding 1s' energized, however, the core 28 is attl'pcted and the lower ends of the members 27 connect the i are elevated above the lower end of the electrode 23. Curved Scrapers 35, each extending about half way about the electrode 23, are carried by the members 27. As the core 2S rises and falls the Scrapers 35 remove from the cylindrical surface of the electrode 23 any material which may have been deposited thereon by the arc.

The lower end of the extension 30 supports in any suitable manner, as by means of screws 36, a globe 37 which surrounds and incluses the are. An aperture 38 may be formed in the lower end of the globe through which air may enter which, when heated by the are, passes up through the annular space between. the members 2O and 31, and through the annular space between the casing walls 8 and 11 and out into the atmosphere over the upper end of the casing wall 11 and below the hood 5. This air serves both to steady the arc and to carry the arc products out of the lamp.

The hood 5 carries binding posts or terminals 35 and 36. A conductor 39 connects the terminal 35 which is the positive terminal of the lamp to one terminal of the winding 7. The other terminal of the winding 7 is connected. to the member 3 by a conductor 40. As shown thev member 3 is electrically connected to the electrode 23 through the platform 6 and member 20 and to the auxiliary electrode comprising the arms 27 through the iexible conductor 29, core 28, and cross-head 27. A conductor 41 connects the negative terminal 36 of the lamp with one of the arms 32. As shown the conductor 41, which is suitably insulated, passes down through the space between the casing walls 11 and 12 and through the space between the members 20 and 31.

If the lamp shown is to be operated in a constant lpotential circuit a steadying resistance in series with the lamp will ordinarily be necessary. lf the lamp is to be operated in a series circuit an automatic cutout will ordinarily be necessary. The steadying resistance or cut-out may be located either within or without the lamp structure. As these devices are well known to those skilled in the art I have not thought -it necessary in the present case'to illustrate either of them.

It will be observed that when the lamp is put in circuit current begins to flow between the terminals through a circuit which includes the negative electrode and the members 27, cross-head 27', core 28 and Winding 7. This will energize the winding, whereupon the core 28 will be raised and the members 27 will be-moved away from the lower electrode, thus starting the arc. The movement of the core 28 is suicient to raise the lower end of the members 27 above the lower end of the electrode 23. As the lower ends of the members 27 move above the these materials may be varied considerably.`

I Ihave advantageously used a composition containing approxlmately 8() parts ot nat- Aural titanifcrousmagnetite containing about 9% of the `titanium oxid, i parts of magnesium oxidand 16 parts Of'chromlum oxld lrg() The magnesium and chromlum oxlds serve to greatly-decrease" the consumption of the electrode from the action of the arc. The

. arcing end of an electrode having the composition above described is apt tobe'come covered with. a film or layer which is a poor conductor of electricity when cold. T he members 27, however, which engage the iron tube or sheath inclosi'ngthe electrode at some distance below the arcing end of the electrode, make-good electrical connections with the electrode. The are drawn'v between the side of electrode 33 and the auxiliary elec-- trode soon warms the arcing end of the electrode up so` that its conductivity becomes fairly good, and the arc ordinarily plays from the side of the electrode 33 for not more than a second or so at starting. I prefer to make electrode 33 with al diameter 'about twice that of the ordinary carbon electrode. IVhen so formed and with the composition described above, a period of one hundred and sixty hours or thereabout will be required to produce an electrode con- I' sumption of one-fourth. of an inch with the 1, lamp from time to time to clean the globe. etc., and see that everything 1s4 workmg properly, may raise the lower electrode at ordinary are currents which I prefer to employ. The lamp disclosed will operate satis-V factorily while the arcincreases one-fourth of an-m'ch fromtpts length at. starting. The attendant. who must necessarlly'mspect the intervals to compensate for its consumption by nlanipulating'the screws 34.

An electrode of the composition above described when employed asa negative elec'- trode gives a luminous or iaming argwhich emits an eliicient.v amount` of white light'. Moreover the'arc flame is quite stable.- -The construction hereinbeforedescribed is simple, reliable, compact, and'easily made. It will be obvious, however, that changes may be made in the form ofthe lampdisclosed without departing from the-spirit of my invention, and thatfcertain features of my invening use of other features. V

tion may be employed,- without. a corresI/irtid4 rwhich is a conductor ofthe first class and `the other composed of a material which is.

l lamp.

What I claiml as newv and desire to secure by Letters Patent of the United. States, is,-. 1. In an arc lamp, the colnbination of a pair of stationary main electrodes yone of liable to become a conductor of the second l class under the action 'of the arc, but is incased in a conductor of the first class, with a movable auxiliary electrode in permanent electrical connection with the first namedstationary electrode, and means for moving it from engagement with the inclosure of the second stationary electrode a distance greater than the distance between the two stationary electrodes.

2. In an arc lamp, a pair of fixed main electrodes one of which is a conductor ofthe irst class and the other composed ofa material which is liable to become a conductor of the second class under the action of the arc, but is --inca'sed in a conductor of the first class, a movablemember 'actuated by the passage of current through the lamp, and

an auxiliary electrode connected thereto' lengaging the casing of the second named stationary electrode when no current is fiowing through the lamp and-moved away from the said casing when current passes through the 3. In an arc lamp, a ,pair of main electrodes, an` auxiliary electrode comprising a pair of members pivoted for relative movements and arranged to engageon opposite sides of one ofthe main electrodesl when the lamp is in the out-of-service condition, and meansl for moving said members away from said latter main electrode and toward the other main elect-rode when the lamp is 'put into4 service. n

4. In an are lamp, a tubular member, a platform carried at one end thereof, a Winding surrounding said'tubular member, a core of magnetic material movably mounted Within said tubular member, a pair of main electrodes secured below-and inline withv said tubular member, and an auxiliary electrode comprising a member pivotally secured to said core vand engagingl the more lemote yof said electrodes when-the`lamp is in the out-ofservice condition. i

5:."In an arc lamp,qa pair of main electrodes between whichan arc extends when the lamp 1s in serv1ce,"av core movable 1n lme with thearcing points of said electrodes, and

an Lesbaped member having one end pivoted to the core and the other end normally held by gravity `in engagement with the side sur-- face of one of said electrodes.

6. In an arc lamp, 'a tubular member, a 125 platformsecuredto said tubular member, a chambered member having itsgup'per end secured to said platform, an electrode secured to the lower end of said chambered member, a movable core movably extending into Aing electrode when'the lamp is in an inopshaped member having one end pivoted to compose said tubular member, one or more L-shaped members each having one end pivotally secured to said core, said L-shaped members extending through slots formed for the pur-l pose in said chambered member, and a second electrode secured belowthe first, said L-shaped members being so arranged that their lower ends engage-the outer surface of said second electrode when the core is in onev position and are separated therefrom when the core is in another position.

7. In an are lamp, a non-consuming electrode, a consuming electrode, a member movable in a direction parallel with the axis of said non-consuming electrode and located above said non-consuming. electrode, an auxiliary electrode carried by said member and arranged to engage'the side of said consumerative condition, and means controlled by the passage of current through said lamp for moving said auxiliary electrode away from said consuming electrode.

8. In an are lamp, a chambered member, a non-consuming electrode secured tothe under side thereof, a second electrode located below said non-consuming electrode,l a movable member located in said chamber, an L- said member, the l parts being so proportioned and arranged that the other end of said 'L-shaped member is held by gravity in engagement with the side of the lower electrodewhen the lamp is in the out-of-service condition, and means controlled bythe passage of current through said lamp for moving said L-shaped member out of engagement with said lower electrode.

-9.,In an arc lamp, a tubulary member, a Astationary upper electrode, a lower electrode of material liable to become a second class conductor under the action of the arc but ineased in a conductor of the first class and xed below said upper electrode, a winding surrounding said tubular member( a core coperating therewith sliding in said tubular member, and a device connected to said core for starting an arc between the casing of the lower electrode and the up per electrode and shifting it from the casing to the body of the lower electrode.

10. In -an arc lamp, a pair of electrodes out of contact with each other, a movable arc starter for starting an arc between said electrodes, and a device operated by the'moves ment of said are starter for removing from one of said electrodes material which may Ohave been deposited thereon from the are.

11. In -an are lamp, a pair of main elecy trodes, an auxiliary electrode, means for causing it to move into and out of engagement with the side of one of said electrodes to start an are therefrom, and a device actuated by the movements of said auxiliary electrode for removing from the other of #shaped member having one end pivoted to said main elect-rode material which may have been deposited thereon from the are.

yr12. In an are lamp, an electrode from the eid of which an arc extends in the normal operation of the lamp, a second electrode having a portion adapted to engage the side of the tirst mentioned electrode when the lamp is in the out-of-service condition, and means for moving said second electrode in a direction parallel to the length of the first mentioned electrode to move said portion away from said rst mentioned electrode thereby7 drawing an arc between the electrodes when the lamp is connected in circuit.

13. In an are lamp, a casing comprising two walls one within the other, said walls being separated from eachother and formed with openings or passages through them, a spacing member between said walls formed with one set of passages which register with said passages in said walls, and with another set of passages which lead from the space between said walls at one side of said member to the space between the walls at the opposite side of said member. 1

14. In an arc lamp, a casing comprising two walls one within the other, said walls being separated from'each other toy form a chimney space through which the arc prod.- ucts may pass and being provided with openings or passages through them, said member between said wall being formed with one set of passages which register with said passages in said walls and with another set of passages which lead from the space between said walls at one side of said member to Vthe space between said walls at the opposite side of said member.

15. In' an arc lamp, a pair of main elec trodes between which'an are extends when the lamp is in service, an electromagnet and a corearmature for the same movable in line with the axis of said electrodes, and an L- the c'ore and in permanent electrical connection with one electrode, and theother end normally' held by gravity in engagement with the side surface of -the other electrode.

16..In an are lamp, a pair of stationary main electrodes, a'movable auxiliary electrode in permanent electrical connection with one of said main electrodes and normally engagin' the other electrode at.a region removed viirom-its main arcing surface, and means for moving it from this position to a position which is separated from the second named electrode by a distance greater than the distance 'between the main arcing surfaces of the fixed electrodes.

In witness whereof, I have hereunto set my hand this 29th day of April, 1905.

, JOHN T. H. DEMPSTER. iVitnesses BENJAMIN B. HULL,

HELEN Onronn. 

